Liquid strainer



D 0, 9 F. s. WINFIELD 3,486,625

I LIQUID STRAINER I Filed D90. 11, 1967 ATTORNEYS United States Patent 3,486,625 LIQUID STRAINER Frederick S. Winfield, 375 Chalfonte, Grosse Pointe Farms, Mich. 48236 Filed Dec. 11, 1967, Ser. No. 689,469 Int. Cl. B01d 33/04, 35/02; C02c 1/18 US. Cl. 210-232 17 Claims ABSTRACT OF THE DISCLOSURE A strainer unit of the suction type is disclosed for use in systems requiring the continuous circulation of a liquid, such as hydraulic power fluid, a coolant or lubricant, in a machine tool or other installation, etc., wherein it is desired to filter and maintain the circulant free of foreign matter, dirt or other contaminating solid material.

The strainer is essentially composed of a suitably sustained, generally cylindrical screen, shown as being of an axially corrugated or ribbed cross-section, which screen is replaceably mounted coaxially between opposed stamped end caps. One of these is in effect imperforate and the other cap is shown as having an improved type of threaded tubular fitting fixed thereto, as by welding, brazing or the like. However, the cap and fitting may be of onepiece construction. In either case, the fitting part carries a rolled thread, at which it is removably applicable to the suction or intake line of a pump or like circulating means of the equipment.

The strainer further comprises an axially elongated, U-shaped bracket disposed within the screen and welded, brazed or otherwise fixedly secured to the suction-side end cap of the strainer, on the flat inner surface of that cap. The opposite imperforate endcap has means coacting with an adjacent end of the U-bracket in performing two functions.

One of these is that of securing the last-named end cap rigidly to the bracket, hence to the remainder of the strainer structure, with the corrugated screen held axially between the caps. The other purpose or function of the means in question is to drivingly couple the imperforate end cap to the bracket in a rotative sense, hence to the other, fitting-equipped end cap, in such manner that a manual twist of the bracket-connected end cap imparts torque to the strainer structure as a whole, under which the latter may be readily and quickly screwed into or off the pump intake line, as in cleaning or replacing the strainer screen.

As herein shown, the torque applying means comprises a small pin welded, brazed or otherwise fixedly secured to the inner surface of the imperforate end cap 'at a point spaced radially outwardly of :a center screw which connects that cap to the U-bracket within the screen. This affords a torque arm by which manual twisting effort, applied on a larger torque arm at the periphery of the cap, is transmitted through the bracket to the opposite end cap and its threaded fitting.

Background of the invention Field of the invention The improved strainer or filter, as indicated above, was devised for use at the end of the suction line of a coolant, hydraulic power liquid, lubricant or like circulating pump, typically one in the power system of a machine tool. The strainer is removably attached to the suction line, being disposed in the usual collecting tank or sump to which the liquid returns from the power or equivalent unit of the system to be strained and recirculated. However, the mechanical principle of the invention, as embodied in a highly simple and inexpensive yet rugged Patented Dec. 30, I969 structure, is obviously also well adapted for use in many other settings than those instanced above.

I am unaware of any prior art reference relating pertinently to the special improved structure of the subject strainer. However, the improvement constitutes a considerable refinement and simplification of a similar strainer earlier devised by me, which is threadedly attached to the pump suction line through the agency of a large hexnut spun onto the suction end cap.

Summary of the invention My previous strainer is improved upon in one respect by the subject unit in that it eliminates considerable difficulty and expense of attaching the mentioned nut of the earlier structure to the suction end cap of the strainer. This in turn stems from the fact that the union of the nut was accomplished by outwardly spinning an integral skirt extension of the nut into tight gripping engagement with the suction end cap in a zone directly surrounding its central aperture. Added to this special, deforming-type operation was a separate weld-type attachment of the U-bracket to the inner surface of the cap, at points just outwardly of the connection of nut to cap.

In contrast, pursuant to the improvement of the invention the suction end cap is united to both the threaded fitting and to the arms of the U-bracket by welding or brazing in a single operation. This represents a great ad- Vance in point of greater simplicity and speed of assem-- bly, coupled with a lower cost of parts, as compared with my previous strainer structure.

Likewise, the need to apply a wrench to the nut in removing and replacing the strainer represented a certain inconvenience, which is overcome by utilizing the relatively large diameter, imperforate end cap for a manual grasp and twist in the removal and replacement of the strainer unit. In this connection, the invention assigns a dual function to the imperforate end cap and a pair of connectors associated therewith, i.e., the function of rigidly holding the two end caps and strainer screen in axial assembly and the function of drivingly connecting these parts for rotative threading and unthreading manipulation by hand.

Brief description of the drawing FIG. 1 is a perspective view of the strainer of the invention;

FIG. 2 is an enlarged scale view, partially broken away and in axial section through the structure;

FIG. 3 is a view in horizontal section on line 3-3 of FIG. 2; and

FIG. 4 is a view, partially broken away, in horizontal section on broken line 44 of FIG. 2.

Description of a preferred embodiment The improved strainer is generally designated by reference numeral 10, being constituted, as best shown in RIG. 2, by a centrally apertured upper or suction end cap 12 of flanged circular shape, an opposite, substantially imperforate end cap 14, an inner cylindrical, perforated or foraminate support sleeve 16 and an outer strainer screen 18. The caps 12, 14 are preferably sheet metal stampings of cup-like cross-section, and sleeve 16 is an elongated metal cylinder having a multiplicity of rather generous sized perforations 19. Sleeve 16 may be fabricated of a blank of sheet metal stock rolled to circular crosssection and welded along a seam paralleling its axis.

As best shown in FIG. 4, the screen 18 is also of generally cylindrical cross-section, but is longitudinally corrugated at 20 about its circumference, the corrugations extending the length of and paralleling the axis of the screen and sleeve 16. Their radial depth is such that screen 18 telescopes quite snugly about the sleeve and also, as sustained radially by the latter, telescopes quite snugly into the two end caps 12 and 14 at the respective cylindrical flanges or walls 22, 23 thereof. Screen 18 and sleeve 16 abut at their tops and bottoms against their respective caps 12, 14, so that a sufficiently tight edge seal on the end caps results, without need for further gasketing.

The screen 18 may be of Monel metal, of cadmium plated or unplated steel, or of any other material not subject to deterioration in the contemplated surrounding. The mesh size of the screen may vary, for example, from 60 mesh (0.009) to 200 mesh (0.0035), but this of course will vary depending upon the type or temperature of the liquid circulated, the pressure drop across the unit as affected by the pumping rate, etc.

In accordance with the invention, an axially elongated bracket 24, in the form of a length of steel strap bent into a generally U-shaped section which is rectangular at its base or cross part 25, is rigidly secured, as by welding or brazing, directly to the inner surface of suction end cap 12, and just diametrically outwardly of a central opening 26 of substantial size in the cap. The connection is made at integral out-turned top tabs or arms 27 of bracket 24. The axial length of the bracket is Such that its bottom cross part 25 is spaced a bit above bottom cap 14; and a securing screw 29 extends upwardly through a central hole in the otherwise imperforate cap 14, taking threadedly into a central punched boss 30 of the end cap.

Further in accordance with the invention, the suction end plate 12 is completed by a coupling fitting member 32 of stamped sheet metal having internal threading 33 rolled thereon. This is preferably a single start helix of proper pitch and axial length to permit its being taken up and backed off manually, yet still to effect a union to the suction line sufficiently tight to withstand vibration.

An integral annular, radially out-turned top flange 34 of fitting 32 overlies the top of suction end cap 12 outwardly of the latters central aperture 26, where it is rigidloy united to the cap by welding or brazing. This union is preferably effected simultaneously with the fused connection of the bracket tabs 27 to the cap 12, using appropriate fixture means. Fitting 32 is shown in FIG. 2 as threadedly receiving internally thereof the nipple-like end 35 of a pump intake pipe 36.

As indicated above, it is contemplated that the cap 12 and its fitting 32 may be of an integral, one-piece nature with the threading 33 rolled on a tubular formation stamped in the cap part, which formation is axially somewhat shorter than that of fitting part 32.

Finally, the opposite end cap 14, as shown in FIG. 2, has a small torque-transmitting pin element 38 welded or otherwise secured at an enlarged head 39 thereof to the inner surface of the cap, in radially outward spacing from the holding screw 29 on the axis of the cap. Pin 38 projects through an opening 40 in the cross part 25 of U-bracket 24, with only sufiicient side clearance to enable the pin to be located readily in opening 40 when the cap is frictionally applied to screen 18.

Accordingly, with the cap 14 thus drivingly coupled by pin 38 to the bracket 24, the latter may be manually twisted to correspondingly rotate the bracket and, through the latter, the suction end cap 12 and its threaded fitting 32. Thus, the strainer structure is, without rec urse to wrench means, rotated as a whole to thread or unthread it in relation to pipe 36.

The strainer is seen to be inexpensively, efficiently and ruggedly constituted by simple parts assembled to one another in a quick, easy and inexpensive manner. Like the strainer screen 18, the other associated sleeve, fitting, bracket and cap parts may be plated, if desired or necessary, to protect the same against deterioration in the operating surrounding. Removal of the holding screw 29 enables the screen and sleeve components to be dismantled to any desired degree, either Wholly or as to any of its constituent parts. The screen 18 is easily and quickly 4 separated from sleeve 24, since these components are held in assembly to one another solely by friction.

What is claimed is:

1. A strainer or like device adapted to be threadedly coupled to a fluid line, comprising annular, axially extending strainer means having an annularly flanged closure cap applied to an end thereof, with said strainer means telescoped in the flange of the cap, said end cap having an opening of substantial size and a threaded tubular member coaxial with said opening, said member being threadedly engageable with said line, a bracket fixed on said end cap, the other end of the device having another annularly flanged cap telescopingly receiving said strainer means, and means connecting said other cap to said bracket in a manner to move the latter rotatively about the axis of the strainer means and thereby rotate said end cap and said device as a whole for threading action relative to said fluid line.

2. A strainer or like device adapted to be threadedly coupled to a fluid line, comprising cylindrical strainer means having annularly flanged caps frictionally and removably applied to opposite axial ends thereof solely by relative axial movement of the caps and strainer means, said ends of said strainer means being telescoped in the respective caps, one of said end caps having an opening of substantial size and a threaded tubular member coaxial with said opening and disposed substantially in its entirety axially within said strainer means, said member being threadedly engageable with said line, a U-shaped bracket fixed on said one end cap and extending axially within said strainer means toward the other end cap, said other cap having means releasably connecting the same to the cross part of said bracket in a manner to move the latter rotatively about the axis of the strainer means and thereby, upon rotation of said other cap, to rotate said one cap and said device as a whole for threading action relative to said fluid line.

3. The device of claim 1, in which said connecting means comprises a first connector engaging said bracket to hold said other end of the device to the bracket, and a second connector engaging said bracket to rotatively couple said other end to the bracket.

4. The device of claim 2, in which said connecting means comprises a first connector removably and centrally engaging said cross part of the bracket to releasably hold said other end cap to the bracket, and a second connector engaging said bracket cross part in radially offset relation to the first connector to rotatively couple said other end to the bracket.

5. The device of claim 1, in which said threaded tubular member and said bracket are rigidly connected to said end cap on opposite surfaces of the latter.

6. The device of claim 2, in which said threaded tubular member and said bracket are rigidly connected to said one end cap on opposite surfaces of the latter, said member and bracket being outwardly flanged and offset, respectively, at these connections.

7. The device of claim 3, in which said threaded tubular member and said bracket are rigidly connected to the said end cap on opposite surfaces of the latter.

8. The device of claim 4, in which said threaded tubular member and said bracket are rigidly connected to said one end cap on opposite surfaces of the latter, said member and bracket being outwardly flanged and offset, respectively, at these connections.

9. The device of claim 6, in which said threaded tubular member is a sheet metal stamping.

10. The device of claim 8, in which said threaded tubular member is a sheet metal stamping having an annular flange about a threaded body thereof at which its connection to said one end cap is externally effected.

11. The device of claim 1, in which said one end cap is a stamping, the threading of said tubular member being rolled thereon.

12. The device of claim 2, in which said one end cap is a stamping, the threading of said tubular member being rolled thereon.

13. The device of claim 3, in which said one end cap is a stamping, the threading of said tubular member being rolled thereon. .1

14. The device of claim 4, in which said one end cap is a stamping, the threading of said tubular member being rolled thereon.

15. The device of claim 1, in which said strainer means comprises a cylindrical screen member having corruga- 10 tions about its periphery extending axially thereof.

16. The device of claim 2, in which said strainer means comprises a cylindrical screen member having corrugations about its periphery extending axially thereof, and a cylindrical foraminate sleeve telescoped within said screen member.

17. The device of claim 4, in which said strainer means comprises a cylindrical screen member having corrugations about its periphery extending axially thereof, and

a cylindrical foraminate sleeve telescoped within said screen member.

References Cited UNITED STATES PATENTS 555,831 3/1896 Stiner 210460 X 2,366,451 1/1945 McNeal 210 232 X 354,930 12/1886 Pike 210 453 X 2,608,302 8/1952 Mattel 210460 2,382,278 8/1945 Widmann.

FOREIGN PATENTS 110,800 5/1939 Australia.

REUBEN FRIEDMAN, Primary Examiner T. A. GRANGER, Assistant Examiner US. Cl. X.R. 210-460 

